A masterwork material is used in some Schematics that have a "masterwork slot". These materials provide special effects that no other crafting material can provide in any other slot and are very powerful in comparison, with possibilities such as greatly increasing critical crafting (+10% to final item stats).

Fade-Touched Stormheart Effect

Berserk: 30% damage bonus, 300% damage from all sources 10% chance to use Shield Bash on a hit